Producing isoprene.



UNITED s A'rEs PATENT OFFICE.

FRANZ WEIBEL, 0F MANNHEIM, GERMANY, ASSIGNOR T0 BADISCHE ANILIN & SODA FABRIK, OF LUDWIGSHAFEN-ON-THE-RHINE, GERMANY, A CORPORATION.

PRODUCING ISOPRENE.

No Drawing.

Patented Dec. so, 1913.

(H C:C:C(CH,) byheating the latter with a contact substance containing alumina,

preferably in cacao.

The following example will serve to illustrate further the nature of this invention, which, however, is not confined to this xample: Asymmetrical dimethyl allene of boiling point from 39 to 41 C. is passed, in the form of vapor, through a tube containing granulated alumina heated to-about 3 00 one sidefor allowing the. dimethyl-allene to be supplied drop by drop and is connected on the other side with 'alvaeuum pump so as to maintain a pressure of from 20 to millimeters. The vapors leavingthe tube pass through a condenser cooled with carbon dioxid and ether, whereupon practically which is provided with means on pure isoprene of boiling point' 32 to 34 C. is obtained.

Now what I claim is 1. The process of preparing isoprene which, consists in passing the vapors of asymmetrical dimethylallene over a heated catalytic agent.

2. The process of producing isoprene by heating asymmetrical dimethyl-allene with 35 alumina.

3. The process of producing isoprene by heating asymmetrical dimethyl-allene with alumina in vacuo.

4. The process of producing isoprene by passing vaporized asymmetrical dimethylallene over alumina at a temperature of about 300 C. and at a pressure of about from 20 to 30 millimeters.

In testimony whereof I have hereunto set my hand'in the presence of two subscribing witnesses.

FRANZ VVEBEL.

Witnesses: Y J. ALEo. LLOYD, A. O. TILLMANN. 

